How is obstructive sleep apnea diagnosed?
Dec 27, 2012
The doctor, usually a GP (general practitioner, primary care physician) at first will ask the patient about symptoms and daytime drowsiness/sleepiness. This will probably be followed by a physical examination, which will include checking the patient's blood pressure.
Blood test - this may be done to rule out any thyroid problems.
Nocturnal Polysomnography - records brain wave changes, eye movements, leg movements, blood oxygen levels, muscle tone, heart rhythms and respiration during sleep. This test helps rule out other possible conditions. A series of electrodes are placed in various parts of the body. This is carried out in a hospital or specialized sleep clinic.
Oximetry - an oximeter is a small sensor that is placed on the finger and sends out light pulses. The sensor is attached to a computer which can measure blood oxygen levels in real time. This test can be done at home.
Epworth sleepiness scale - this scale measures the patient's level of daytime sleepiness, which may help in the diagnosis of sleep disorders. It was introduced by Dr. Murray Johns, Epworth Hospital, Melbourne, Australia. The patient completes a short questionnaire which asks about probabilities of falling asleep in 8 different situations - the patient rates the probabilities on a scale from 0 to 3. A score of 0 to 9 is considered normal, anything above that indicates a higher risk of a sleep disorder.
The Epworth sleeping scale is repeated after treatment to determine whether the patient has improved.
The National Health Service (NHS), UK has three ratings for OSA (the patient may have to spend a night in hospital or specialized sleep clinic for testing):
· Mild - the patient has 5-14 episodes of apnea or hypopnea per hour
· Moderate - 15 to 30 episodes of apnea or hypopnea per hour
· Severe - over 30 episodes of apnea or hypopnea per hour